Inkjet style printers typically utilize one or more pens held in a carriage that moves across the paper from side-to-side, with each pen having multiple nozzles organized as a vertical array, and an advance or "slew" mechanism, for advancing a sheet of paper (or other appropriate ink-receiving medium) beneath the pen (i.e., from top to bottom). Thus the advance mechanism moves the paper to the proper line, and the inkjet pen then moves laterally across the paper into position to print a band or swath whose height is limited by the vertical dimension of the nozzle array, and whose width is determined by the corresponding dimension of the sheet. After the selected nozzles are "fired," creating a single column of dots ("pixels") of ink, the pen continues in its lateral movement across the width of the sheet until it reaches the position where the next dot of ink is required. To avoid pixels "running together" ink may be applied to adjacent pixels in separate passes, allowing the first to at least partly dry before the second or subsequent pixels are created. Once the current swath is completed, the advance mechanism moves the page such that the lateral path of the pen is lower in the page and the process is repeated until the page is printed.
The known prior art designs require that the printer housing be large enough to accommodate the lateral movement of the pen, thereby establishing minimum dimensions for both the volume and the "footprint" (e.g the area occupied by the cabinet). Furthermore, multi-lead flexible cables typically provide power and control signals to the moving pen from a fixed power supply and control circuitry inside the housing, adding to the cost and complexity of the printer and potentially resulting in undesirable radio frequency interference. Also, the moving pen must either be connected to a remote reservoir of ink (thereby adding further cost and complexity) or the pen must contain a built-in ink reservoir (which increases the moving mass and therefore consumes additional power). Space and power consumption are of particular concern for portable applications, as a smaller and less costly device is understandably preferred.